DEVELOPMENT OF A FRICTION STIR WELDING FIXTURE FOR JOINING MATERIALS ON A VERTICAL MILLING MACHINE

Abstract

Friction stir welding process is a challenging task due to the high cost of Friction Stir Welding (FSW) machine and inability of the existing fixture to weld hard metals. A motorized friction stir welding fixture with capable of welding metals. The developed fixture is suitable to adapt a vertical milling machine for carrying out friction stir welding operation was developed. The axial force required for obtaining adequate friction stir welding joints on the FSW fixture was thoroughly research and established from literature. Hence its value was used to design the FSW fixture. CREO, a computer aided design (CAD) software, was used to develop the geometric model of the design, conceived from brainstorming. The detailed design parameters of the FSW features were obtained using existing design equations applied to the FSW fixture design concept. Subsequently, the fixture was fabricated and evaluated. To evaluate the developed fixture, friction stir welding of aluminium (A1100) were conducted using the fixture on a vertical milling machine available in The School of Engineering central Workshop. Physical observation of the weldments and the measurement of their selected mechanical properties (tensile and hardness) was done. Also, the motion accuracy of the fixture drive system was investigated by comparing its actual movement with the programmed movement. The physical appearance of the weldments produced revealed that the fixture was able to produce weldment of good quality. The feed rate was found to be directly proportional to the tensile strength and inversely proportional to the hardness of the weldments. The motion accuracy of the drive system was estimated as 74.56%. Base on the results of the tensile strength and the hardness tests carried out on the weldments produced using the developed fixture, the joint efficiency was found to be 77.32% and 78.79% respectively. The relationship between the feed rate and measured mechanical properties was found to be in agreement with what obtained in the existing studies.